* [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON
@ 2020-03-21 19:31 Daniel Lezcano
2020-03-23 3:18 ` Viresh Kumar
2020-03-24 2:30 ` Amit Kucheria
0 siblings, 2 replies; 3+ messages in thread
From: Daniel Lezcano @ 2020-03-21 19:31 UTC (permalink / raw
To: daniel.lezcano
Cc: Amit Daniel Kachhap, Viresh Kumar, Javi Merino, Zhang Rui,
Amit Kucheria, open list:THERMAL/CPU_COOLING, open list
The WARN_ON macros are used at the entry functions state2power() and
set_cur_state().
state2power() is called with the max_state retrieved from
get_max_state which returns cpufreq_cdev->max_level, then it check if
max_state is > cpufreq_cdev->max_level. The test does not really makes
sense but let's assume we want to make sure to catch an error if the
code evolves. However the WARN_ON is overkill.
set_cur_state() is also called from userspace if we write to the
sysfs. It is easy to see a stack dumped by just writing to sysfs
/sys/class/thermal/cooling_device0/cur_state a value greater than
"max_level". A bit scary. Returing -EINVAL is enough.
Remove these WARN_ON.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/thermal/cpufreq_cooling.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index af55ac08e1bd..d66791a71320 100644
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev,
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
/* Request state should be less than max_level */
- if (WARN_ON(state > cpufreq_cdev->max_level))
+ if (state > cpufreq_cdev->max_level)
return -EINVAL;
num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus);
@@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
int ret;
/* Request state should be less than max_level */
- if (WARN_ON(state > cpufreq_cdev->max_level))
+ if (state > cpufreq_cdev->max_level)
return -EINVAL;
/* Check if the old cooling action is same as new cooling action */
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON
2020-03-21 19:31 [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON Daniel Lezcano
@ 2020-03-23 3:18 ` Viresh Kumar
2020-03-24 2:30 ` Amit Kucheria
1 sibling, 0 replies; 3+ messages in thread
From: Viresh Kumar @ 2020-03-23 3:18 UTC (permalink / raw
To: Daniel Lezcano
Cc: Amit Daniel Kachhap, Javi Merino, Zhang Rui, Amit Kucheria,
open list:THERMAL/CPU_COOLING, open list
On 21-03-20, 20:31, Daniel Lezcano wrote:
> The WARN_ON macros are used at the entry functions state2power() and
> set_cur_state().
>
> state2power() is called with the max_state retrieved from
> get_max_state which returns cpufreq_cdev->max_level, then it check if
> max_state is > cpufreq_cdev->max_level. The test does not really makes
> sense but let's assume we want to make sure to catch an error if the
> code evolves. However the WARN_ON is overkill.
>
> set_cur_state() is also called from userspace if we write to the
> sysfs. It is easy to see a stack dumped by just writing to sysfs
> /sys/class/thermal/cooling_device0/cur_state a value greater than
> "max_level". A bit scary. Returing -EINVAL is enough.
>
> Remove these WARN_ON.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/thermal/cpufreq_cooling.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
> index af55ac08e1bd..d66791a71320 100644
> --- a/drivers/thermal/cpufreq_cooling.c
> +++ b/drivers/thermal/cpufreq_cooling.c
> @@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev,
> struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
>
> /* Request state should be less than max_level */
> - if (WARN_ON(state > cpufreq_cdev->max_level))
> + if (state > cpufreq_cdev->max_level)
> return -EINVAL;
>
> num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus);
> @@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
> int ret;
>
> /* Request state should be less than max_level */
> - if (WARN_ON(state > cpufreq_cdev->max_level))
> + if (state > cpufreq_cdev->max_level)
> return -EINVAL;
>
> /* Check if the old cooling action is same as new cooling action */
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON
2020-03-21 19:31 [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON Daniel Lezcano
2020-03-23 3:18 ` Viresh Kumar
@ 2020-03-24 2:30 ` Amit Kucheria
1 sibling, 0 replies; 3+ messages in thread
From: Amit Kucheria @ 2020-03-24 2:30 UTC (permalink / raw
To: Daniel Lezcano
Cc: Amit Daniel Kachhap, Viresh Kumar, Javi Merino, Zhang Rui,
open list:THERMAL/CPU_COOLING, open list
On Sun, Mar 22, 2020 at 1:01 AM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> The WARN_ON macros are used at the entry functions state2power() and
> set_cur_state().
>
> state2power() is called with the max_state retrieved from
> get_max_state which returns cpufreq_cdev->max_level, then it check if
> max_state is > cpufreq_cdev->max_level. The test does not really makes
> sense but let's assume we want to make sure to catch an error if the
> code evolves. However the WARN_ON is overkill.
>
> set_cur_state() is also called from userspace if we write to the
> sysfs. It is easy to see a stack dumped by just writing to sysfs
> /sys/class/thermal/cooling_device0/cur_state a value greater than
> "max_level". A bit scary. Returing -EINVAL is enough.
>
> Remove these WARN_ON.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
> ---
> drivers/thermal/cpufreq_cooling.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
> index af55ac08e1bd..d66791a71320 100644
> --- a/drivers/thermal/cpufreq_cooling.c
> +++ b/drivers/thermal/cpufreq_cooling.c
> @@ -273,7 +273,7 @@ static int cpufreq_state2power(struct thermal_cooling_device *cdev,
> struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
>
> /* Request state should be less than max_level */
> - if (WARN_ON(state > cpufreq_cdev->max_level))
> + if (state > cpufreq_cdev->max_level)
> return -EINVAL;
>
> num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus);
> @@ -434,7 +434,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
> int ret;
>
> /* Request state should be less than max_level */
> - if (WARN_ON(state > cpufreq_cdev->max_level))
> + if (state > cpufreq_cdev->max_level)
> return -EINVAL;
>
> /* Check if the old cooling action is same as new cooling action */
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-03-24 2:30 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2020-03-21 19:31 [PATCH] thermal/drivers/cpufreq_cooling: Remove abusing WARN_ON Daniel Lezcano
2020-03-23 3:18 ` Viresh Kumar
2020-03-24 2:30 ` Amit Kucheria
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